Dolomite: Perspectives on a perplexing mineral

Abstract

Dolomite is a metastable mineral that can precipitate directly from solutions containing magnesium, calcium and carbonate to form cement or unlithified sediment. It can be categorized into two classes such as penecontemporaneous dolomites, which form immediately after deposition of carbonate precursors as a result geochemical conditions that exist within the precursor's environment of deposition. Postdepositional dolomites form after carbonate sediment deposited and subsequently removed from the active zone of sedimentation. The factors that influence the dolomite reservoir quality include the permeability, solubility and original depositional fabric of a carbonate rock or sediment and the chemistry, temperature and volume of dolomitizing fluids. The porosity of dolomite decreases during the early stages of dolomitization in mud-dominated carbonates and the mechanical compaction in the buried dolomite further reduces porosity. Higher porosity and permeability tend to preserve in dolostone as the structure of dolomite crystals provides greater compressive strength.